A pupil of Reni in Bologna in the mid 1630s Cagnacci also visited Venice and was in Rome at the height of Caravaggio’s influence there. An allegory is a symbolic story. The snake devouring itself is an ancient Egyptian symbol interpreted as the eternal cycle of creation while the skull is a reminder of the transience of life on earth. Other symbols include the dandelion, a bitter herb and common Christian symbols of grief: candles, an hourglass and ruined buildings.